Frequently an upper string needs to be anchored to a packer to support tools on the string such as an electric submersible pump. Such tools block access below the packer and on some occasions need to be removed from the wellbore for maintenance. Typically the packer has an associated barrier valve that needs to be closed when the upper completion is released from the packer. To hold the upper completion to the packer generally in a polished bore receptacle an anchor or disconnect is used. There are several concerns with such applications that are run in together attached to the packer. There is the concern of an unintentional disconnection such as when setting the packer with internal pressure or when trying to get the assembly to advance to the desired location. In tools that disconnect with an applied force to break a shear pin there is also a concern that the stretch in the string at the time of release would provide a violent ricochet and damage some of the parts such as the actuator attached to the packer barrier valve.
Tools that release with the breaking of a shear pin or the flattening of a stack of Belleville washers are known for example in U.S. Pat. No. 6,053,262. Some tools replace collets and shear pins in a disconnect to gain full circumferential support in a locked position as in U.S. Pat. No. 7,426,964.
Devices have been used to reduce shock in the context of dropped tools that have a crushable nose as in U.S. Pat. No. 7,779,907 while others allow a controlled release of parts in a manner to avoid damage to the parts using a multi-dimensional pin in a bore that allows pulling to get a surface signal of landing in a casing collar before sufficient pin movement in the bore to allow a reduction of applied surface force before any release of components. This device is illustrated in US Publication 2011/0056678. U.S. Pat. No. 6,367,552 shows a travel joint that is held together until applied force meters fluid through an orifice to then permit enough relative movement to unlock the travel joint components for relative movement.
What is lacking in these tools is options for the release that also address in the space limitations of subterranean tools a way to control which release mode is operative at any given time and the ability to minimize damage to associated components when the release would otherwise be violent such as breaking one or more shear pins with a release force applied to a string. The present invention provides hydraulic release or actuation as the primary mode of operation. When operating in this mode the shear release mechanism can be protected from stress from forces applied to the string. Optionally the locking feature that protects the shear device can be disabled for normal operation of the tool with the packer set. If for any reason the manipulation of hydraulic pressure in the control line to the tool does not permit a release by a simple pull on the string a shear device is broken but with travel limited so that disconnection does not occur. Instead a shock absorbing member provides the needed relative movement for defeating the shear member while absorbing the shock of the release. Reversing the relative movement then releases fully two adjacent components so that collets can be undermined for a low force separation that will not harm the barrier valve actuation system that is still engaged to the anchor or disconnect as the upper sting comes out of the hole. While one application is described those skilled in the art will appreciate that other tools can benefit from the described designs in the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.